Reheat turkey, potatoes, squash, greens, and Brussels sprouts in an oven or microwave.

To assemble the parfait, use a spoon to layer the turkey, squash, greens, and cranberry sauce in individual parfait glasses. Finish with an ice-cream scoop of mashed potatoes, and top with a roasted Brussels Sprout.

As for the level of difficulty, it's as easy as assembling an ice-cream parfait. Active prep time takes about 10 minutes. One possible shortcut: If you have a microwave oven, assemble the parfait whole to begin with, then microwave it all at once.